Process for the thermal treatment of carbonaceous material



Patented Oct. 12, 1943 OF CARBONACEO'US MATERIAL Wilhelm Michael, Ludwigshafen-on-the-Rhine,

Otto Goehre, Heidelberg; Gerhard Free and Fuener, Ludwigshafen-on-the- Rhine, and: Wilhelm Schneider, Mannheim, Germany; vested in the Alien Property Custo- Wilhelm v.

dian No Drawing. Original application July 30, 1938,

Serial No. 222,144. Divided and this application July 13, 1940, Serial N0. 345,:67. Germany August 9, 1937 6 Claims.

The present invention relates to a process for the thermal treatment of carbonaceous material.

We have found that highly efiicient catalysts for the thermal treatment of carbonaceous materials, more particularly for the splitting of these materials, are obtained by mixing moist mineral gels with a metal salt solution and heating the mixture, if desired after the addition of a precipitant.

The gels are prepared from the solution of these salts of the elements of the 3rd and 4th groups of the periodic system which are capable of forming gels, especially of silicon, titanium, zirconium, thorium, cerium or aluminum, by the addition of suitable precipitants, as for example acids or salts.

The catalyst may be prepared by mixing the gel, preferably a silica gel, precipitated from a silicate solution or a mixture of several gels with a solution of one or several metal salts, especially salts of the metals of the 2nd to the 8th groups of the periodic system, and more particularly of magnesium or aluminum, of titanium, tin, zinc, and the metals of the 5th, 6th or the iron group and then heating the mixture in order to eliminate the whole or the bulk of the moisture. For this purpose the mixture may for exmple be evaporated to dryness, whereupon'heat- 1g is preferably continued up to temperatures of 50 C., or even higher, say of the range of from 300 to 400 C., in order that the metal salts de posited on the gel are converted into other compounds.

The mixture of gel and metal salt solution may also be evaporated at about 100.C., filtered, prior to dryness washed, if desired, for removing the precipitant employed for the preparation of the gel, then dried and, if desired, heated up to a higher temperature.

The gel may also, before the addition of the metal salt solution, be freed from the precipitant and then further used in the manner described.

The precipitant may also be-added tothe gel before the addion of the metal salt solution. It is not necessary to separate the gel from the aqueous liquid prior to adding the metal salt solution or the precipitant.

The catalysts may also be prepared by mixing of solutions of gel-forming. substances with solutions of one or more metal salts without practiavoided in known manner for example by theiad cally any-precipitation taking place and subse quently adding one or more precipitants to mixture. The formation of a precipitate dition of acids, such as dilute hydrochloric a d The precipitant should be capable of precip tating both the gel and the metal salt. FOIlIthlS. reason it is sometimes necessary to use more that one precipitant. "I'he precipitant may als'os' added in such manner that for example the. agents promoting formation of the gel is first addedaandrg then the agent serving to precipitate .the metalssalt. j The preparation of the catalystmay'also carried out in the presence of bleaching ar or bauxite or similar substances. 1

The gel is filtered oil from the solutiomalong? I with the metal compound precipitated, washed for removing particularlythe' alkaline precipjie tant and dried. Itmay be advantageousrtoieiss pose the catalyst to high temperatures iffidesiredin the presence of 'reducing gasesbefore' it9'.'use, for example by slowly heating it'to from 45il 0 800 C. The gel and the metal salt solution are mixed in such a proportion that the catalystinontains from about 10 to .98 per cent, for instance-;fiiom to 90 per cent of the gel. For the racking and destructive or refining hydrogenation iproce esses such catalysts are very suitable as contain from about 1-0 to per cent, preferably fronrlill to 75 per cent of gel. 'When'using for prep:- aration of such a catalyst silica as gel an na as gel or as the metallic component together with other gel-forming or met stances, the ratio of S102 to AlzOa than about '75 to 25. :5

The following table shows for *exampl the metallic constituents of catalysts sult'able for th thermal] treatment of carbonaceo fi'sf material, prepared in the said manner, but tli" invefi is not restricted to the use of these Si-Mg Together with one or more Zn, 811, Ti, V, Cr, Mo,

2. The catalyst may also be mixed it according to the present or more, at ordinary,

' as hydrogen.

naceou substances. as for example graphite or lignite small coke, shaped and then heated to from about 500 to 600 C.

is done while intensely stirring.

fact that its eiiiciency can be easily restored to the full initial value by a treatment, for example with oxidizing gases, at an elevated temperature.

This treatment maybe carried out at high temperatures up to about 800' C. whereas when regenerating siliceous catalysts not obtained by precipitation from solutions of gel-forming subadvantage in the catalyst prepared invention reside in the efliciency, even when stances, for example natural bleaching earths; Y

temperatures surpassing about 500' 0. must not be employed as otherwise the catalyst would be damaged. The maintenance of such a low temperature in regenerating the catalyst wherein exothermic reactions take place is only possible with a careful control of the temperature and of the oxygen content of the oxidizing gases used and is therefore very troublesome.

In the cracking and hydrogenation processes the formation of gaseous substances is considerably reduced by the use of the said catalysts if the metal or metal compounds are completely or partially dissolved out for instance with the aid of inorganic or organic acids. The resulting product is then freed from acid, preferably by washing, dried and brought into a suitable shape.

The efiiciency of the catalyst may be still further increased by an addition of boric acid. The use of the latter type of catalyst results in a specially high output of a highly anti-knock benzine.

The boric acid may be added to the gel in a solid or liquid form either before or after the addition of the metal salt solution or the precipitant, or after the filtration, or before or during the heating.

The amount of boric acid added may vary within wide limits, the preferred amount being from 0.5 to 30 per cent calculated with reference to the dry mixture of gel and metal compound.

The catalysts claimed or mixtures thereof are especially adapted for use in splitting carbonaceous materials, such as mineral oils, tars, extraction products of solid carbonaceous materials, cracked products, destructive hydrogenation products of coal, tars, mineral oils or wood, or oils produced synthetically from carbon monoxide and hydrogen, as well as fractions of the said oils. The splitting is preferably carried out at temperatures of between reduced or increased pressure,- for example at between 10 and 200 atmospheres, if desired in the presence of gases, such steam, nitrogen or oxides of carbon.

The catalysts are also very suitable for the hydrogenation of the said substances particularly when working at pressures above 300 atmospheres, for instance 400 to 800 atmospheres. In this case preferably a catalyst is used containing silica and alumina and if desired in addition thereto metals as magnesium, iron, cobalt, nickel, tungsten, molybdenum, chromium, manganese, vanadium or uranium or their comp unds in amounts from 0.5 to per cent or more.

When using as initial materials for cracking or hydrogenation processes hydrocarbons very rich in hydrogen for instance hydrocarbons obtained by the reaction of carbon monoxide with hydrogen, pure paraffin-basic petroleums or hydrocarbons rich in hydrogen obtained by pressure hydrogenation and/or with the aid of selective solvents and which contain at least 15 grams of hydrogen for each 100 grams of carbon, or fractions of the said substances, not only is a good yield of benzine obtained but there is only a relatively small formation of gas if multi-component catalysts are used which have been prepared in the said manner by mixing gel substances with a magnesium salt solution. A catalyst containing mainly magnesia and silicic acid and preferably also a small amount of zinc is especially suitable.

Other thermal treatments of carbonaceous substances for which the said catalysts are suitable are the polymerization, alkylation, isomerizing, desulphurizing and refining of hydrocarbon oils.

The following example will further illustrate how the said invention may be carried out in practice but the invention is not restricted to this example. The parts are by weight unless otherwise stated.

Example 1.5 kilograms of 28 per cent waterglass solution are diluted to 10 litres with water and then a solution of 650 grams of ferric chloride (FECIILGHaO) in 2 litres of water is added while stirring. The resulting precipitate is separated by filtration, washed, dried by heating to about 40 C. and then washed with 10 per cent hydrochloric acid until there is no further yellow coloration of the acid. The residue containing silicic acid is then washed with water until it is free from acid, dried by heating to about 100 C., shaped and exposed to a temperature of 400' C.

If this catalyst be used for splitting for example a middle oil fraction prepared from hyleast one catalytically acting metal compound,

about 300 and 700 C.

the improvement which comprises redissolving with acids at least a substantial portion of the catalytically acting metal compound as the final step in establishing the composition of the cata- 'lyst.

the improvement which comprises drying said metal compound is re-dissolved after heating the mixture.

5. A process according to claim 1 in which the catalytically acting metal compound is redissolved until the washing acid remains free of ions of the catalytically acting metal.

6. In a process for cracking a hydrocarbon oil at a temperature between 300 and 700 C. in the presence of a catalyst obtained by heating to a temperature of at least 250 C. an initially moist non-alkaline mixture of silica hydrogel and at least one catalytically acting metal compound, 

